Microwave Heating Device Phase Shift Control for Uniformity
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Solution Overview
Problem
Existing electromagnetic heating techniques, particularly microwave heating devices, face challenges in achieving homogeneous temperature distribution within food products and ensuring uniform heating of multiple identical loads, leading to non-uniformity in heating outcomes.
Innovation Solution
A microwave heating device and method that utilize a microwave generating system with multiple radiating portions emitting microwaves of the same frequency but with different phases, allowing for operational configurations that create a 'stirring' effect by adjusting phase shifts to optimize energy efficiency and achieve spatial uniformity through constructive and destructive interference patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If microwave heating is used to achieve shorter thawing or cooking times, then heating speed is improved, but temperature distribution uniformity deteriorates
Solution Approach 1:
The microwave generating system is divided into multiple independent radiating portions (at least two), each capable of being controlled separately in terms of phase and power. This segmentation allows different regions of the food product to be heated independently, enabling better control over temperature distribution while maintaining fast heating speeds.
Solution Approach 2:
The system dynamically adjusts the phase shifts between different radiating portions during the heating process. By changing phase relationships in real-time, the system can adapt to variations in food product geometry, composition, and heating progress, thereby maintaining both speed and uniformity throughout the heating cycle.
2Productivity
If multiple identical loads are heated simultaneously, then productivity is improved, but heating uniformity among loads deteriorates
Solution Approach 1:
Each load is targeted by specific radiating portions, allowing independent control of energy distribution to different loads. This enables the system to maintain uniform heating across multiple loads simultaneously by adjusting the phase and power of individual radiating portions based on the specific configuration and absorption characteristics of each load.
Solution Approach 2:
The system incorporates detection means to monitor the heating process and a control unit that adjusts the phase and power of radiating portions based on detected temperature or energy absorption patterns. This feedback mechanism ensures that all loads receive appropriate energy distribution, maintaining uniformity even when heating multiple items simultaneously.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method ensures improved spatial uniformity and energy efficiency in heating, particularly when heating multiple identical loads simultaneously, by selecting operational configurations that maximize energy absorption and minimize temperature differences across the product.
Implementation Method 1
emitting microwaves of the same frequency but with different phases, allowing for operational configurations that create a 'stirring' effect by adjusting phase shifts to optimize energy efficiency and achieve spatial uniformity through constructive and destructive interference patterns
Implementation Method 2
heat is generated directly inside the food product by means of electromagnetic fields or electromagnetic radiations. Amongst these, some techniques use radio frequency (RF) dielectric heating and other techniques use microwaves (MW)
Data Source
AI summary
A microwave heating device includes radiating portions adapted to radiate microwaves to the heating chamber and is operated according to operational configurations that differ in frequency or in phase shift(s) between the radiated microwaves. A learning procedure is executed by sequentially operating the radiating portions in several operational configurations. Energy efficiency data are calculated for those operational configurations. An operating frequency is selected based on energy efficiency data. An operational configuration with a maximum energy efficiency at the selected operating frequency is taken as a reference. A heating procedure is executed by sequentially operating the radiating portions in operational configurations having the selected operating frequency and respective phase shift(s) chosen around the respective phase shift(s) of the reference operational configuration. The phase shift(s) of each chosen operational configuration may have a phase shift distance from the respective phase shift(s) of the reference operational configuration, such that, in the space of the phase shifts, the reference operational configuration is surrounded by the chosen operational configurations.